Triple lap roofing

A triple lap, in roofing terms refers to how much overlap there is between each layer of a roof covering; slate, shingle etc. A triple lap means each layer covers a third of the layer beneath, meaning three layers overlap (triple). This type of roof is less common but sometimes used for slate roofing in coastal areas where extra weather proofing is required and shingle roofing.

Double lap roofing is general the most common standard whereby each layer covers the layer beneath by about or less than half, so that two layers (double) overlap to create a water resistant roof cover. This type of lap might be used with tiles, slates, shingles or shakes.

Examples of triple lap slate roofing can be found on the North coast of Devon and Cornwall, often using locally produced Delabole slate. A particular type of triple lap slate roof is the scantile roof which includes a bedding mortar of lime between the slates at a the edges, adding further resistance to strong winds and salty sea water.

Both double and triple lap roofs are laid from the eaves towards the ridge of the roof a row at a time, fixed into the roof battens with roofing nails. Roofing nails are short nails with a large flat round head to secure the slate or tile, and either a smooth or a corrugated shank for a more secure fixing.

Because slate roofs are laid in this process with the next layer above covering the fixings of the layer below, acces to those fixings for repair or replacement can be difficult. As such many slaters or slate roofers will posses a slaters ripper or puller, which is a long thin tool (slightly longer than a slate) which can be inserted and slid from outside at the angle of the pitched of roof to rip the nail fixing the broken slate out.

[edit] Related articles on Designing Buildings

• Battens.
• Ceiling tiles.
• Ceramic tiles.
• Clovelly, a village changing hands and changing with the times.
• Conservation.
• Delabole Slate.
• Domestic roofs.
• Double lap roofing.
• Flashing.
• Flat roof defects.
• Heritage.
• Historic environment.
• IHBC articles.
• Institute of Historic Building Conservation.
• Nails - a brief history.
• Photocatalytic tiles.
• Pitched roof.
• Planning for sustainable historic places.
• Reconciling conservation and sustainable development.
• Roof coverings.
• Roof insulation.
• Roof slates.
• Roof tiles
• Roofing defects.
• Shingle roofing.
• Sustaining Clovelly, a history, its management and retrofit.
• Thatch roofing.
• Tiles.
• Tile roofing
• Types of nails.
• Types of roof
• Weatherboarding